Apparatus for superheating steam by means of a high-pressure medium



o. HARTMANN Feb. 15, $27.

APPARATUS FOR SUPERHEATING STEAM BY MEANS OF A HIGH PRESSUfiE MEDIUIFiled June 4. 1921 s ShqetS-Sheet flltarlzeys Invezzibr.

Feb. 15, 1927.

o. HARTMANN APPARATUS FOR SUPERHEATINGSTEAM BY MEANS OF A HIGH PRESSUREMEDIUM Filed June 4. 1921 5 Sheets-Shasta Feb. 1 5 r1927.

I o. HARTMANN APPARATUS FOR SUPERHEATING STEAM BY MEANS OF A HIGHPRESSURE MEDIUI 3 Shets-Sheet 3 Filed June 4- 1921 Mttorneys PatentedFeb. 15, 1927.

OTTO HARTMANN, F CASSEL-WILHELMSHOHE, GERMANY, ASSIGNOR T0 SCHMIDTSCHEHEISSDAMPF-GESELLSCHAFT, M. B. H., A CORPORATION OF GERMANY.

APPARATUS FOR S UP ERHEATING STEAM. BY MEANS OF A. HIGH-PRESSURE MEDIUM.

Application filed June 4, 1921, Serial No. 475,172, and in GermanySeptember 24, 1919.

(GRANTED UNDER THE PROVISIONS OF THE ACT MARCH 3, 1921, 41 STAT. L,1313.)

The invention relates to improvements in apparatus for superheatingsteam by means of a high-pressure medium flowing through a tube systemarranged in a container through which passes the steam to besuperheated.

The forms of apparatus of this type sugested hitherto have notsatisfactorily fulfilled the necessary practical requirements,

1 the chief of which are: the provision of a large heating surface in asmall space; simplicity and ease of production; and ready accessibilityfor cleaning purposes.

In general the only suitable heating media for the purpose in questionare water under high pressure or the steam therefrom, which for anypractically useful degree of superheat must possess a pressure of atleast 30 atmospheres corresponding toa temperature of 233 C.

With the objects in view, it is natural to employ a still higherpressure and tempera.- ture, for example, 100 atmospheres or even 150atmospheres and more, corresponding in the case of water to atemperature of 300 and 340 respectively.

' The heating surfaces for giving off the heat required for superheatingwith high pressures of the order above mentioned, must necessarily beconstructed as tube systems in order to provide the necessary strength,the arrangement being preferably such that the high-pressureheating-medium flows through a tube system immersed in the steam to besuperheated.

In order to satisfy the requirement of small space in conjunction withlarge heat ing surfaces, the tubes must be of small bore and theindividual tubes or coils must be arranged as close together as possiblein order to reduce the cross-sectional area available for flow of thesteam to be superheated, so that the latter attains a high velocity andis subjected to a considerable degreeof agitation. The number of tubesor coils of tubes to be dealt with, each with its inlet and outlet end,is thus considerable, even when the quantity of steam to be heated issmall.

The principle on which the present inven tion is based consistsininserting the ends of the tubes of a tube system arranged in acontainer into inlet or outlet chambers in such a Way that the walls andfastenings of the latter'a're subjected to the least possible stress, sothat they may be of. minimum dimensions, a practicable heat-transmissionapparatus in a compact form being thus ensured.

The above principle is realized in practice by closely packing the endsof the tubes arranged in a container into the walls of suitable inletand outlet chambers in such a way i that the area of the surface inwhich the open ends of these tubes lie is itself'considerably less thanthe cross-section of the tube system. I

By the expression cross-section of the tube system is to be understoodthe area enclosed by the outer limiting lines of the 7 tube system in aplane perpendicular to its longitudinal axis. I

In this manner, the inlet and outlet chambers which are under highpressure can be given small dimensions, the manufacture of the apparatusbeing thereby facilitated oW-' ing to the elimination of impracticablethicknesses of metal.

In addition the tube systems are connected together in one or moregroups so that they may be readily removed for cleaning Withoutemploying bolts or joints of undesirable size.

' Further, it is desirable in order to obtain the highest efliciercywith the new appara- 35 tus that the individual paths for the heatingmedium should be either equally long or of approximately the sameresistance to flow. If concentrid coils oftubes are used for the heatingsurfaces, an approximation to the theoretical efiiciency is obtained ifthe bore of the tubes of the outer set of coilsis in a known manner madelarger than that of the inner set of coils so as to counterbalance theirgreater length and heating surface. l/Vltll equal tube diameters theresistance to flow would be too great in the outer coils andconsequently the efficiency of the heating surfaces would be low,

It is also desirable in apparatus construct- 7 ed of coils of tubes thatthe individual convolutions should be given such a diameter that theycan be screwed one into the other and thereby break up and agitate thesteam flowing past them; it coils oi tubes of the requiring a largeamount of space and leavm a large cross-sectional area available for theflow of steam so that the turbulent or whirling action has been small.

According to one type of the present invention the coils of tubes arewound rightand left-handed with a clear space between adjacentconvolutions somewhat greater than the outside diameter of the tubes sothat the coils can be inserted laterally one into the other, andspecialsupports tor the individual convolutions dispensed with.

The use or boils of tubes wound rightand left-handed and insertedlaterally one into the other has also the advantage that, in addition tothe circular form, any cross-section whatever of the container can becompletely filled with coils so that no dead spaces obcur.

It is a further advantage of a heat-trans mission apparatus according tothe present invention that no air or water ockets occur in the tubesystem through whmh the heating medium flows. a

In the drawings the invention is shown in different forms by way ofexample.

. Figure 1 is a central vertical section of a heat-transmissionapparatus with a single group of tube coils screwed one into the other,only the upper and the lower portions of the coils being shown, theirintermediate portions beingomitted for the sake of clearness; Fig. 2 is'a partial vertical section on an enlarged scale, showing the diiierencein the bore of the coils according to their distance from the center ofthe apparatus, the

bore being shown uniform in Fi 1, for the sake of convenience; Fig. 3 1sa plan view of the lower portion of the a paratus, with the coilsomitted; Figs. Ann 5 are a. vertical section and a plan similar to Figs.1

and 3, respectively, but showing another. form of my invention; Fig. '6is a horizontal section through the central portionof Fig. 4; Figs. 7,9,11 and 13 are partial-vertical sec tions illustrating the lower portionof four additional forms of my invention; Figs. 8,

. 10, 12, and14 are partly sectional plan views A, which is closed bytwo covers, g, each provided with a. chamber, f. Each chamcorrespondingto Figs. 7, 9, 11 and 13, respectively; Figs. 15 and 16 are a verticalsection and a plan similar to Figs. 1 and 3 respectively, but showing afurther form of my invention.

' Refer'rmg toFigures 1 to 3, a tube system, B, isarranged in acontainer or casing,

receiving heat from the neiaguie her, f, is closed by a plate, 6, heldin its place by screws, h, while a rod, Z, holds the plates, 6, togetherso asto facilitate the removal of the tube system, B. This systemconsists of a number of coils of tubes, 0, the bore of which increasesfrom the centre towards the periphery 'or outer wall oi the container,A, i. e., the coil of tubes with the smallest bore is arranged in theimmediate neighbourhood of the rod, Z, andthat with the largest borenear the outer wall of the container, A. This arrangement is showndiagrammatically in Figure 2. The ends of each of the coils, c, are benttowards the rod, Z, and pass into the plates, 6 so as to lie within theplane area, X, of the inlet or out.- let chamber, f. drawings, the area,vX, is. considerably smaller than the cross-section of the tube system,B. For the sake of clearness only the upper and the lower portions ofthe coils a have been shown in Fig. 1 (and the same remark will apply toFigs. 4 and 15), the intermediate coil parts, which connect said upperand lower portions, having been omitted. it will therefore be understoodthat there is a continuous path through each coil from the upper chamberf to the lower chamber f. On accountot the small scale on which Fig. lis drawn, the bore of the' coils c has been shown uniform, but it willbe understood that such bore increases from the center or axis (rod Z)outwardly as illustrated by Fig.2. The covers, 9, are provided withbranches, is and 2', the latter for the inlet and outlet .of thehigh-pressure heating medium and the former tor the inlet and outlet ofthe steam to be superheated.

The action of the heat-transmission apparatus shown in Figures 1 to 3 isas follows 2- The' high-pressure 'superheating medium, steam or water,enters through the branch, i, into the inlet chamber, 'f, inthe uppercover, g, andfrom there passes into the coils of tubes, 0, through thetube ends,d, which are secured into corresponding holes in the plate,e,by expanding or otherwise. The coils, c, are staggered and screwed oneinto the other. and, as will be seen from Figure 1, thus lie closetogether. The heating .medium flows through the individual cpils andpasses from their lowerends into the outlet chamber,-f, and so throughthe outlet ,branch, 5. The steam to be superheated passes through theupper branchQk, into the container, A, through which it flows and passesout through the '.branch, 'lo, of

As will be seen from the.

the lower cover, 9, to any place'desired. In

its relatively wide path it passes over and among the individual heatingcoils at a high velocity and is violently a itated, thereby tu es in ahighly elficient manner. v a In consequence of the s ecial bends at theends ofthe individual coi s of tubes and the closely packed arrangementof the latter within as small an area, X, as possible of the inlet andoutlet chambers, the walls,e, can be proportionately thin since bendingstresses are reduced to a minimum; the tensile stresses on the screws,h, are similarly low and the latter can also be made of comparativelysmall dimensions. Such reductions of stress are of great importance inview of the fact that pressures up to 150 at-' mospheres and more haveto be considered. It will be noted that the outermost coil or helix, 0,that is, the helix of greatest diameter, is of smallest axial length,and that the axial length increases as the diameter of the coil orhelix, becomes smaller. I thus obtain at the ends of the apparatus, thestepped arrangement shown clearly in Fig. 1, which enablesme to avoidsharp bends in the tube ends d of even the outermost coil or helix 0.

It will be seen from the drawings, that in addition the whole tubesystem can be readily inserted and removed. It will also be noted thatthe plates 6 to which the tube ends d are secured, are much smaller thanthe covers 9 and are located inside said covers.

7 I thus reduce the weight of the parts connected with said tube ends03, and faclhtate the assembling and the taking apart of the ap aratus.

n FiguresA; to 6 another form of the invention is shown. In this casethe whole tube system consists of several groups, m and n (see Figure6), four main groups, m, being provided while the spaces not occupied bythem are filled by smaller groups, n. Individual groups consist of anumber of co1ls of tubes which are preferably wound rightand left-handedand inserted laterally one into the other so that the coils afford eachabove, I give such a shape to the inlet or other mutual support. Inconsequence of the arrangement of the groups, n, it will be seen thatthe space within the container, A, is utilized to the best possibleadvantage. In view of the use of several groups of coils it is necessaryto arrange several corresponding inlet and outlet chambers, f f 7, etc.

In the particular example shown, the inlet chambers, f f f etc., arearranged in the side walls of the upper cover, whlle the branch is, forthe introduction of the saturated steam is provided on its face or endwall.

In the two forms of apparatus so far described it will be seen that theplate, 6, is subjected to certain bending stresses, but these can beeliminated.- either wholly or in part by givin an appropriate shape tothe inlet and out et chambers. As explained outlet chamber thatthe-eross-sectional' area of said chamber and therefore the area of theplate containing the ends ofthe tube .coils is considerably smaller thanthe crosstainer, and are not as in prevlous examples separated from oneanother as this form of the invention is intended only for heating withstationary steam which is allowed to condense in situ.

Many other forms of apparatus are POSSI- ble without exceeding the scopeof the invention.

I claim: l. Heat-exchange apparatus comprising a casing provided withinlet and outlet for one of the media which enter into heat-exchangerelation, and also provided with heads recessed on their inner faces toform inlet and outlet chambers, coiled tubing located in said casing andadapted to serve for the passage of the other of said media, andinterior members located entirely within the casin and fitted againstthe recessed portions 0 said heads to form inner walls for said inletand outlet chambers, the ends of the tubing being secured to saidmembers and communiw eating with the interior of said chambers.

2. The structure claimed in claim 1, said inlet and outlet chambers andsaid; interior members having a cross-sectional area smaller than thecross section of the coiled tubing. 3. In a heat-exchange apparatus, ashell,

a removable coil system comprising two members adapted to cooperatetherewith to form inlet and outlet chambers, and coiled tubing joiningand passing through said members, each of said chambers being of OTTOHARTMANN.

